1. Field of the Invention
The present invention relates to a telephone conversation resumption system, a telephone conversation resumption program and a telephone conversation resumption method that resume a telephone conversation when the telephone conversation between wireless portable terminals is disconnected, and also relates to a portable terminal and a relay apparatus that are used for the resumption of a telephone conversation.
2. Description of Related Art
In recent years, mobile phones and portable terminals that enable a wireless telephone conversation using an IP phone or the like via wireless LAN have become popular. Thus, we can often see the scene where people talk over a portable phone while moving. Such a portable phone enables a telephone conversation by performing wireless communication with a relay apparatus (e.g., a mobile-phone base station and an access point of wireless LAN). Thus, when a portable terminal in a telephone conversation moves outside a cover area of the relay apparatus, the telephone conversation might be disconnected.
To cope with such disconnection of a telephone conversation, a method of trying to resume the telephone conversation has been proposed (see JP H10(1998)-327465 A, for example). According to this method, when a telephone conversation is disconnected due to deterioration of a communication state, a terminal tries to resume the telephone conversation by automatically redialing at the timing of the recovery of the communication state.
However, when one of the phones on both ends of the telephone conversation moves outside a cover area of a relay apparatus, so that the telephone conversation is disconnected, a speaker of the other phone cannot tell why the telephone conversation aborted suddenly. Therefore, the speaker of the other phone cannot make a judgment whether to wait for a call or to call back. Furthermore, even if the speaker of the other phone tries to call back, he/she cannot know when to make a call because the state of the phone on the other end is uncertain. Moreover, even if the speaker of the other phone calls back, in the case where the phone on the other end is still outside the cover area of the relay apparatus, he/she still has to call back again.
In addition, in the case where a speaker of the phone outside the cover area of the relay apparatus enters the cover area again where the telephone conversation is possible, if the telephone number of the party on the other end is uncertain, he/she cannot redial. In this way, there are problems that the speakers on both ends cannot know the mutual situations, and therefore they cannot resume the telephone conversation easily.